cultmesh-rs: connect() takes a server over any snapshot source

The previous commit's tests did not compile: connect() was typed to the
default Source.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/cultmesh-rs/tests/rudp_document_server.rs

@@ -241,8 +241,8 @@ fn client_on(
     })
 }
 
-fn connect(
-    server: &mut Server,
+fn connect<Q: CultMeshRudpSnapshotSource>(
+    server: &mut CultMeshRudpDocumentServer<Sink, Q, Clock>,
     clients: &mut [&mut CultNetRudpSocketTransportConnection],
 ) -> Result<()> {
     for client in &mut *clients {